Relay with non-interfering indicator



July 27, 1965 G. c. BOYSEN RELAY WITH NON-INTERFERING INDICATOR 3 Sheets-Sheet 1 Filed Oct. '15. 1961 INVENTOR GERD c.aovseraw/w;

ATTORNEY July 27, 1965 G. c. BOYSEN 3,197,597

RELAY WITH NON-INTERFERING' INDICATOR Filed 001;. 13. 1961 3 Sheets-Sheet 2 M m I l 3 INVENTOR GERD C.BOYSEN ATTORNEY United States Patent F 3,1975%? RELAY WiiH NQN-ENTERFERHNG INDKCA'EQR Gerd Q. iioyseu, Milwaukee, Wis, assignor to Allenllradiey Company, ll'iiiwaulree, Wis, a corporation of Wisconsin Filed (lot. 13, 195i, 8oz. No. MSJMS 4 Claims. ($1. Edit-167) This invention relates to protective relays having tripping mechanisms movable between cocked and tripped positions; and it more particularly resides in an indicator for such a relay movable between normal and indicating positions that is prevented from moving toward indicating position by a blocking engagement with the tripping mechanism when the tripping mechanism is in cocked position and is released to move toward indicating position as a result of movement of the tripping mechanism from cocked to tripped positions, whereby manual operation of the indicator can neither operate nor impede the operation of the tripping mechanism.

Protective relays have many uses in electrical control apparatus, and one common use is in motor control circuits with electromagnetic line contactors. In such use a thermal element of the relay is arranged to respond to the motor load current, and the relay contacts are placed in a control circuit for the magnetic actuator of the line contactor. In the event of an overload, the tripping mechanism of the relay causes a relay operation that in turn acts to open the line contactor of the motor control circuit.

Whether a relay is to be used in a motor control circuit or elsewhere, it is quite advantageous to provide an indicator for the relay that serves to show whether or not it has tripped. Some indicators that have previously been developed include a brightly colored or otherwise clearly visible element that is slidably held within an opening in the relay and biased toward a withdrawn or normal position. The indicator element is so placed as to be struck by the tripping mechanism of the relay in a tripping action and is carried thereby to an extended or indicating position with respect to the relay case whereby the indicator element becomes visible to the operator and indicates that the relay has tripped.

Indicators of this type are functionally desirable in that they allow an operator to determine whether an interruption in circuit operation has been caused by the tripping of a relay or by some other cause. Further, in cases where a number of relays are used in protecting a single circuit the indicators enable the operators to determine which one of the several relays may have tripped should an interruption occur thus saving considerable time and effort in locating the point of overload for the purpose of resetting or repair.

This normal indicator construction, is however, sub- "ect to several serious structural disadvantages by virtue of the fact that the indicator element is biased toward normal position and is struck and carried by the tripping mechanism to its indicating position. The direct engagement between the tripping mechanism and indicator element makes it possible to affect the action of the tripping mechanism by manipulation of the indicator element. For example, some relays have an indicator which rests against the movable relay contacts whereby the indicator is moved to an extended or indicating position upon movement of the contacts to open position. In such a construction it is possible by manually depressing the indicator after a tripping action to move the movable contacts toward closed position even in the event of a continuing overload thus giving rise to the possibility of serious damage. Also, the tripping action of such relays can he accidentally or intentionally impeded or prevented by holding the indicator in a depressed position. Still 3,197,597 Patented July 27, 1965 further, should the indicator bind against the case the operation of the tripping mechanism will be affected in that the contacts may not be able to open.

Similar disadvantages arise when indicator elements are actuated by other elements of the tripping mechanism so long as there is the aforementioned direct pushing engagement in which the tripping mechanism moves the indicator to its indicating position. The indicator of this invention, on the other hand, is arranged to have an indirect or blocking engagement with the tripping mechanism in which the tripping mechanism, while in cocked position, blocks the indicator from moving toward indicating position. When the tripping mechanism then moves toward tripped position the indicator is released to move toward indicating position in response to suitable bias means. By virtue of this indirect engagement manipulation of the indicator operates only against the bias means and can neither cause nor prevent operation of the tripping mechanism. Also, any binding of the indicator has no effect on the operation of the tripping mechanism.

Although the indicator construction of this invention may be used with relays of varying designs, it is especi-.

ally useful in trip-free, tamper-free relays. For this purpose, a trip-free tamper-free relay may be defined as one in which manipulation of the rest means can neither cause nor prevent the opening of the relay contacts. The use of an indicator formed according to this invention with such a relay provides the advantages of an indicator without impairing the trip-free or tamper-free properties of the relay.

It is, therefore, an object of this invention to provide a relay indicator construction in which manipulation of the indicator cannot affect the operation of the tripping mechanism of the relay, either in the sense of causing an operation or of impeding an operation.

it is another object of this invention to provide a relay indicator construction especially useful in trip-free tamper-free relays.

it is a further object of this invention to provide such a relay indicator construction in which the tripping mechanism of the relay is in indirect or blocking engagement with the indicator to provide the foregoing advantages.

it is still another object of this invention to provide a specific indicator arrangement in which any deleterious binding or sticking of the indicator does not affect the operation of the tripping mechanism and can be overcome during resetting by unlimited manual force rather than the internal bias elements of the tripping mechanism.

It is a still further object of this invention to provide such a relay indicator that is simple and inexpensive yet sturdy enough to withstand prolonged and repeated use.

It is still another object of this invention to provide a specific space saving construction for such an indicator that is readily adapted to fit within the case of the usual relay.

It is a still further object of this invention to provide an indicator construction readily adapted to make use of lightweight synthetic materials.

Further objects and advantages will appear in the description to follow. In the description reference is made to the accompanying drawings, forming a part hereof, in which there are shown by way of illustration and not of limitation two specific embodiments of this invention.

In the drawings:

FIG. 1 is a front view in elevation with parts broken away and in section of a thermally responsive relay in= cluding the indicator construction of this invention, the elements being shown in the positions assumed subsequent to a tripping action,

FIG. 2 is a rear view in elevation with parts broken away of the relay of FIG.

. screws for control circuit connections.

1, the elements again being in the positions assumed subsequent to a tripping action,

FIG. 3 is a top view with parts broken away of the relay shown in FIGS. 1 and 2,

FIG. 4 is a fragmentary view in section of the relay of FIGS. 1 and 2 taken along the plane 44- indicated in FIG. 2,

FIG. 5 is a fragmentary view in section of the relay of FIGS. 1 and 2 taken along the plane 5-5 indicated in FIG. 2,

FIG. 6 is a view in section of the relay of FIGS. 1 and 2 taken along the plane 66 indicated in FIG. 2,

FIG. 7 is a front view in elevation similar to FIG. 1, but with the elements being shown in the positions assumed prior to a tripping action,

FIG. 8 is a rear view in elevation similar to FIG. 2, but With'the elements being shown in the positions assumed prior to a tripping action, and

PEG. 9 is a fragmentary front view with parts broken away of a relay similar to the relay of FIGS. 1 through 8 but showing a somewhat different embodiment of an indicator construction formed according to this invention, with alternative positions of certain parts being shown in broken lines.

The indicator of this invention is hereinafter described in connection with a trip-free, tamper-free relay of the type disclosed in the copending applications of Robert E. Walters, Serial No. 32,250, now Patent No. 3,096,415, and Gerd C. Boysen, Serial No. 32,372, now Patent No. 3,096,416, the disclosures of which are incorporated herein by reference. As will be pointed out, however, it is not essential that the indicator be used with such a relay, and the invention is adapted for use with relays of varying design. 1

Referring now to FIGS. 1 through 8 and the embodiment of the invention shown therein, the numeral 1 designates a molded case of insulating material which serves to mount the operating elements of the relay. Mounting holes 2 are provided in the case 1, and a pair of stationary contact terminals 3 are secured in place by mounting screws 4. The terminals 3 portions which threadedly receive a pair of terminal The terminals 3 also extend inwardly of the case 1 to present a pair of spacedstationary contacts dwhich are bridged by a movable contact 7 slidably guided in a track 8 formed in the case l. A contact bias spring 9 operates between the case 1 and the movable contact 7 to urge the movable contact 7 toward closed position with the stationary contacts 6.

Referring now to FIGS. 1 and 3, it can be seen that a solder type thermal responsive unit It) is mounted at the top of the case 1 and includes a molded base 11 secured in place by screws 12 and a hollow heat conducting stud 13. extending both above and below the base 11. The stud 13 is held against rotation by a crimped connection with the base 11. On opposite sides of the unit are a pair of busses 14 secured to the case 1 by screws 15. A pair of terminal screws 16 are provided at the outer ends of busses 14 and serve for connecting the relay into a load circuit; and a second pair of terminal screws 17 are provided at the inner ends of the busses 14. Mounted by the terminal screws 17 to bridge the gap between the busses 14 is a heater 18 comprising a coil 19 and a case 20 to protect the coil 19 from air currents. The coil 19 encircles stud 13 and the heat transfer from the coil 19 to the stud 13 is, therefore, a measure of the include upwardly extending When. the heat generated by the current will be freed to rotate and thus serves as an indication of an overload.

Referring now to FIGS. 1, 4 and 5, a rectangular trip member 22 of thin sheet material is slidably mounted in the case 1 by a track 23. A resilient metal pawl 24 having an inwardly turned ear 25 is mounted on the trip member 22 by means of a pin 26 that extends sidewardly of the trip member 22 and is spun over asat 27 to hold the pawl 24 in place. A rivet 28 also serves to hold the pawl 24 in place and extends outwardly of the trip member 22 to provide a blocking element in the form of a carnrning pin 29 having an outer, radially extending flange fit).

The end of the pin 26 remote from the trip member 22 is provided with a rim 31 and a reduced end portion 32; and a spring 33 interposed between the case 1 and the pin 26 serves to urge the trip member 22 to the right as seen in FIGS. 4 and 5, such movement being limited by the length of the track 23 and an inwardly turned trip member ear 34.

An indicator 35 is vertically slidable within a track 36 in the case 1 and is preferably formed of a lightweight synthetic material, such as nylon, of a color clearly contrasting to that of the case 1. The lower end of the indicator 35, as seen in FIG. 1, is of reduced diameter and serves as a seat for one end of a compression spring 38 that is seated at its other end against the case 1 and urges the indicator 35 upwardly. A downwardly inclined working element in the form of an arm 39 is formed integrally with the indicator 35 and provides a camming surface engageable with the pin 23 in a manner to be hereinafter described. of reduced diameter and is slidable within an opening 49 in the case 1 to serve as a visible indicating shaft as will be described.

Referring now to FIGS. '2, 5 and 6, it can be seen that the track 23 also sildably mounts an actuator 41 formed of thin sheet material. The actuator 41 is provided with a longitudinal slot 42 through which the reduced end 32 of the pin 26 extends, and is also provided with an inwardly turned ear 43 spaced from the rim 31 of the pin 26. A spring 4-4 is interposed between the ear t3 and the ear 34 of the trip member 22 and serves to urge the actuator 41 to the left as seen in FIG. 5. The actuator 41 is also guided in its movement by means of a second slot and a pin 46.

The actuator 41 is also provided with a downwardly extending portion 47 which is turned inwardly at its lower end to form a platform 53 on which is mounted a rod 45 of'complex configuration. The rod 49 has a free end 5t which projects between the stationary contacts 6 and is engageable with the movable contacts 7.

A clocking lever 51 in the form of a ell crank is 'rnounted on the actuator portion 47 by a pin 52 passing in the positions'of FEGS. 1 and 2. The cocking lever 51 is normally held so that the pin 52 is at the left-hand end of the slot 53, as seen in FIG. 2, by means of a spring 57 connected at one end to an inwardly turned ear 5%; of

the lever 51 and at its other to'the platform 48 and rod 49.

- The reset lever 56 is vertically slidable in a complementary recess of case 1 and is held captive by a pin 59 extending through a slot 69. The lever 56 is also guided by means of a lower projection 61 that fits within a slide 62 formed in the case 1. The reset lever 56 is provided at .its upper end with a manually engageable cap 63, seen in FIG. 1, and at its lower end with a downwardly extending operating finger 6 i parallel to and spaced inwardly from the projection 61. A grasshopper spring 65 is The upper end 37 of the indicator 35 is also mounted at its center by a pin 65 formed in the case 1. The shorter leg of the spring 65 is anchored against the case 1 and the longer leg engages in an opening 57 in the reset lever 56 to urge the reset lever 56 in an upward direction as seen in FIG. 2.

The thermal unit it), trip member 22, actuator ll, contacts 6 and '7, reset lever as, cocking lever 51 and their associated elements together constitute a tripping mechanism, the operation of which will now be described. Normally, the elements of the tripping mechanism are in the positions shown in FIGS. 7 and 8, in which the tripping mechanism as a whole is said to be in a cocked position. The the cocked position, the alloy between the stud 13 and ratchet 21 is in a solid state, whereby the ratchet 21 is prevented from rotating. The pawl ear 25 is engaged by the ratchet 21 and serves to hold the trip member 22 against the bias of the spring 33 in a position to the right as seen in FIG. 7, termed a latched position.

When the tripping mechanism is in cocked position, with the trip member 22 in its latched position, the blocking element or camming pin 2? is in engagement with the upper end of the camming surface of the working element or arm 39, whereby the indicator 35 is held against the spring 38 in a downward position referred to as a normal position. The pin 29 normally blocks the indicator 35 from moving upwardly in response to the spring 38 and in this normal position the shaft 3? of the indicator 35 is withdrawn within the opening 40 and is not clearly visible from the outside of case 1.

When the trip member 22 is in its latched position, the actuator 41 is held by the spring 44 in a position, termed a retracted position, to the left as seen in FIG. 8. With the actuator 41 in its retracted position, the reduced end 32 of the pin 26 is held at the right-hand end of the slot 42 as seen in FIG. 8 and the free end 5%) of the rod 49 is spaced from the movable contact '7. The spring 9 is thus free to move the movable contact '7 into a closed position with respect to the stationary contacts 6 to complete a control circuit through the relay.

In the event of an overload, the various elements of the tripping mechansm move to the positions shown in FIGS. 1 through 6, in which the mechanism is said to be in a tripped position. When an overload occurs, the stud 13 is heated as previously described, thus freeing the ratchet 21 to rotate and disengage the pawl ear 25 under the bias of the spring 33. The trip member 22 is, therefore, moved to a position to the left as seen in FIG. 1, which is termed its operating position.

In the movement of the trip member 22 to operating position, the camrning pin 2% is moved out of its blocking engagement with the upper part of the arm Sh, thus releasing the indicator 35 to be moved upwardly by the spring 38 to what is said to be its indicating position in which the shaft 37 extends through the opening 4% and becomes clearly visible from without the relay. The travel of the trip member 22 is so arranged that upon completion of its movement with the trip member 22 to operating position the pin 29 is in engagement with the lower end of the arm 39 and is thus in position to exert a carnrning force on the camming surface thereof during resetting of the relay as will hereinafter be described.

As the trip member 22 moves to operating position, the engagement of the portion 32 of the pin 26 with the end of the slot 42 causes the actuator 41 to be moved to the right as seen in FIG. 2 to its actuating position. During such movement of the actuator 4-1, the free end 5t; of the rod 4) comes into engagement with the movable contact 7, moving the same to the right, as seen in FIG. 2, against the spring 9 to open position whereby the control circuit through the relay is broken.

After the tripping mechanism has moved to tripped position, it may be reset to cocked position by means of the reset lever 56 and cocking lever 51. As can be seen in FIG. 8, the lever 51 is normally in a position in which the working arm 55 is to the left of the vertical path of 6 the working finger 64 of the reset lever 56. With the elements in this position, the reset lever may be depressed without having an effect on the tripping mechanism since the finger 64 will bypass the arm 55.

When the tripping mechanism moves to tripped position, the lever Si), by means of the pin 52 and the reduced end 32 of the pin 26, is carried with th trip member 22 and actuator 4-1 to the position shown in HG. 2 in which the arm 55 is directly under the finger 64. When the lever 56 is then depressed, the lever 51 is pivoted in a counterclockwise direction, as seen in PEG. 2, and its upper end, through the pin 26, exerts a force on the trip member 22 causing the trip member to be moved to the left and to- Ward its latched position. At the same time, a resultant force acting on the pin 52 serves to hold the actuator 41 in its actuated position, whereby the movable contact '7 is held in open position throughout resetting thus prevent ing damage in the event of a continuing overload. The relative movement between the actuator and trip member 22 during resetting is taken up by the spring 44 which is thereby loaded.

As the pin 29 moves, with trip member 22, to the right as seen in PEG. 1 or toward the latche position of the trip member 22, it slides along the cainming surface presented by the arm 39 and exerts a camrning force that forces the indicator 35 downwardly against the spring 3% to return the indicator 35 to its normal position.

When the reset lever 55 has been depressed and the trip member 22 moved to latched position, the pawl ear 25 will again be in a position to engage the ratchet 21. The lever se may then be released and if the alloy between the stud l3 and ratchet 21 has cooled sulficiently to prevent rotation of the ratchet 21 the elements will assume the positions of FIGS. 7 and 8 with the indicator 35 in normal position, the loaded spring 44 serving to move the actuator 41 to retracted position upon release of the lever 56. If the alloy has not sutliciently cooled, the tripping mechanism will again assume a tripped position and the indicator 35 will, therefore, again move to indicating position as previously described.

The provision of the slot 53 enables the relay to have a trip free action even if the lever should be depressed while the tripping mechanism is in cocked position, thus giving rise to the possibility of a blocking engagement between the finger 6d and arm 55' should a tripping action occur. The slot 53 provides a lost motion connection between the actuator 41 and cocking lever Sit which allows the actuator 41 to move to actuated position regardless of such blocking engagement.

In FIG. 9 there is shown an alternative indicator construction for use with the relay of FIGS. 1 through 8. The relay on which the alternative embodiment is shown is identical with that of FIGS. 1 through 8 and the visible elements therein have been assigned like numbers. Th indicator construction itself, however, is indicated generally at 68 and includes a generally V-shaped tlat spring 69 the lower leg of which is anchored. against the case It. A cylindrical indicator '70, of a bright metal construction, is mounted at its lower end in a slot 71 at the free end of the upper leg 72 of the spring 69 and is slirlable within the opening at}. The spring 69 urges the indicator 76 up wardly, and the inclined leg 72 is a working element similar to the arm 39 and presents a camming surface that is engageable with the pin 29. In this embodiment, therefore, the working element is actually formed as a part of the bias means, spring 69, as opposed to the first embodiment in which the arm 3% is integral with the indicator 35. The leg 72 is, however, connected to the indicator 7t through the medium of the slot 71, so that in both embodiments the Working element is operatively connected to the indicator to provide for operation by the pin 29.

The normal position of the indicator 7d is shown in broken lines in FIG. 9, and it can be seen that the upper leg 72 of the spring 69 is held downwardly against the inherent resiliency of the spring 69 by a blocking engagement with the pin 29 when the trip member 22 is in latched position. The indicator 7th is then withdrawn and is not clearly visible through the opening 40. When the trip member 22 moves to the left toward operating position, however, the upper leg '72 is released to spring to the full line or indicating position of PEG. 9 wherein the indicator 7% is moved upwardly to become visible to an operator through the opening 4% In a resetting action, the pin 29 slides along and exerts a camming force on the working surface presented by the upper leg '72 to force it, with the indicator 7t), downwardly to normal position. The slot 71 serves to allow relative lateral movement at the connection between the leg 72 and indicator 7%) to prevent the binding of the indicator 7%) within the opening 40, both during tripping and during resetting, which might be caused by the arcuate path of movement of theleg 72.

In'each embodiment of the invention, there is provided an indicator, 35 or 7%, bias means, 3% or 63, and a working element, 39 or 72. In each case a blocking element associated with the tripping mechanism, the pin 29, serves by a blocking engagement with the working surface to prevent the indicator from moving toward indicating position while the tripping mechanism is in cocked position. When the blocking element is moved from its blocking engagement with the working element, the indicator is freed to assume an indicating position in response to the bias means. When the blocking element moves with the tripping mechanism to cocked position, it operates through a camming surface of the workingelement to return the indicator to normal position.

In both embodiments, manual depression of the indicator has no effect on the operation of the tripping mechanism since such movement of the indicator operates only on the bias means. Also, should the indicator bind against the case, the tripping mechanism remains entirely free to move to tripped position. The fact that the indicators are operated by the bias means also allows these elements to be constructed of lightweight synthetic materials, since they are not subjected to the heavy stresses which might occur it they were struck by the tripping mechanism in a tripping 'movement.

In both embodiments herein, a radial-type camming engagement is used in which movement of the tripping mechanism in one line results in movement of the indicator along a perpendicular line. This arrangement is often advantageous and in the relay herein, for example, is space saving and allows for the indicator element to project through the more readily visible top of the relay case. It would be entirely feasible within the scope of the invention, however, to provide a translatory linkage in which the tripping mechanism and indicator move along parallel lines. Also, although the indicators shown are normally retracted, a minor rearrangement would enable the provision of an indicator that is normally extended and retracts upon occurrence of an overload.

Although it has been necessary in the interest of full disclosure to describe in somedet-ail the structure and function of the particular relay shown herein, it will be obvious that the indicator of this invention may be incorporated in relays or" greatly differing designs, so long as there is provided a tripping mechanism that moves from cocked to tripped positions. 7 This invention is, however, particularly useful with a trip-free, tamper-free relay of the type herein since it enables the provision of an indicator without impairing these desirable properties of the relay.

Even in a relay of the type disclosed herein, minor variations are possible and within the scope of the invention. It is not necessary to the invention as such, for example, that the blocking element be associated with the trip member of the tripping mechanism, and blocking elements carried by the actuator or movable contact would serve equally well; The disclosed arrangement, however,

a is particularly useful since the unlimited force which can be exerted on the reset lever is available, should the indicator stick or bind in indicating position, to move the indicator toward normal position upon resetting. If the indicator had to be moved toward normal position after resetting ,by the movable contact 7, for example, only the force of the spring 9 would be available and severe binding might prevent the contacts from closing.

Since there are within the scope of this invention a number of variations, the invention is not intended to be limited except insofar as such limitations appear in the following claims I claim:

1. In a relay the combination comprising: an indicator movable between normal and indicating positions and having a working element operatively associated therewith; bias means to urge the indicator toward indicating position; and a tripping mechanism including a trip member movable between latched and operating positions, said trip member having a driving portion thereon and a blocking element that blockingly engages the working element when the trip member is in latched position to hold the indicator in normal position and drivingly engages the working element when the trip member is moved toward latched position to move the indicator toward normal position, means to move'the trip member toward operating position, a contac-tactuator movable between retracted and actuating positions and engageable by the driving portion to be carried to actuating position upon movement of the trip member to tripped position, actuator :bias means to urge the actuator toward retracted position, cocking lever means movable with the actuator and engageable' with the actuator and trip member, and reset lever means engageable with the cocking lever means only when the cocking lever means is in a position corresponding to the actuated position of the actuator, said reset lever means upon engagement with the cooking lever means causing the cocking lever means to move the trip member toward latched position while holding the actuator in actuated position.

2. In a relay the combination comprising: a tripping echanism reciprocally movable between cocked and tripped positions; a pin member mounted on and reciprocally movable with the tripping mechanism along a line of movement; an indicator that is reciprocally movable between normal and indicating positions along a line of movement generally transverse to the line of movement of the pin; bias means operating against the indicator to urge the indicator toward indicating position; and an arm member having one end connected to the indicator and extending therefrom to present an inclined surface extending across the line of movement of the pin, the pin and arm being blockingly engageable when the tripping mecharism is in cocked position to hold the indicator against the bias means in normal position, such blocking engagement being released when the tripping mechanism moves to tripped position to free the indicator to be moved to indicating position, the pin being adapted to cammingly engage the inclined surface or" the arm as the tripping mechanism moves toward cocked position to thereby move the indicator toward normal position.

3. In a relay the combination comprising: a case; a tripping mechanism reciprocal-ly movable in the case between cocked and tripped positions along a generally horizontal line in a given vertical plane; a pin member mounted on'and extending sidewardly from the tripping mechanism to be reciprocally movable therewith along a generally horizontal line that is in a vertical plane spaced from and parallel to the plane in which the tripping mechanism moves; an indicator that 'is separate from the tripping mechanism and is reciprocally movable in the case along a generally vertical line between an upper indicating position and a lower normal position; bias means operating against the indicator to urge the indicator upwardly toward its indicating position; and'a generally straight arm member that lies in the plane of movement of the pin member and is inclined with its upper end attached to the indicator, the arm extending downwardly and away from the indicator across the line of movement of the pin member to he engageable therewith, the pin member being blockingly engageable with the upper portion of the arm when the tripping mechanism is in cocked posit-ion to hold the indicator downwardly against the bias means in its normal position, such blocking engagement being released as the tripping mechanism moves toward tripped position to free the indicator to be moved upwardly toward indicating position, the pin member being cammingly engageable with the arm to move the indicator downwardly toward normal position as the tripping mechanism moves toward cocked position.

4 A relay according to claim 3 in which the bias References Cited by the Examiner UNITED STATES PATENTS 2,055,183 9/36 Sperry 200-116 2,177,775 10/ 39 Jackson 200-116 2,375,881 '5 45 Zeller 200-116 2,685,011 7/54 Boller et al 200-116 3,096,415 7/ 63 Walters 200-1 16 BERNARD A. GILHEANY, Primary Examiner.

ROBERT K. SCHABFER, Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,197,597 July 27, 1965 Gerd C. Boysen It is hereby certified that error appears in the above numbered petent requiring correction and that the said Letters Patent should read as corrected below.

Column 1, line 37, after "relay" insert case line 49, for "operators" read ope'rator column 2, line 26, for "rest" read H reset column 4, line 52, for "clocking" read cocking column 5, line 13, for "The" read In column 6, line 3, for "an" read any Signed and sealed this 18th day of January 1966.

EAL) west:

RNEST w. SWIDER EDWARD J. BRENNER :tcsting Officer Commissioner of Patents 

1. IN A RELAY THE COMBINATION COMPRISING: AN INDICATOR MOVABLE BETWEEN NORMAL AND INDICATING POSITIONS AND HAVING A WORKING ELEMENT OPERATIVELY ASSOCIATED THEREWITH; BIAS MEANS TO URGE THE INDICATOR TOWARD INDICATING POSITION; AND A TRIAPPING MECHANISM INCLUDING A TRIP MEMBER MOVABLE BETWEEN LATCHED AND OPERATING POSITIONS, SAID TRIP MEMBER HAVING A DRIVING PORTIONN THEREON AND A BLOCKING ELEMENT THAT BLOCKINGLY ENGAGES THE WORKING ELEMENT WHEN THE TRIP MEMBER IS IN LATCHED POSTIION TO HOLD THE INDICATOR IN NORMAL POSITION AND DRIVINGLY ENGAGES THE WORKING ELEMENT WHEN THE TRIP MEMBER IS MOVED TOWARD LATCHED POSITION TO MOVE THE INDICATOR TOWARD NORMAL POSITION, MEANS TO MVOE THE INDICATOR TOWARD NOROPERATING POSITION, A CONTACT ACTUATOR MOVABLE BETWEEN RETRACTED AND ACTUATING POSITIONS AND ENGAGEABLE BY THE DRIVING PORTION TO BE CARRIED TO ACTUATING POSITION UPON MOVEMENT OF THE TRIP MEMBER TO TRIPED POSITION, ACTUATOR BIAS MEANS TO URGE THE ACTUATOR TOWARD RETRACTED POSITIONCOCKING LEVER MEANS MOVABLE WITH THE ACTUATOR AND ENGAGEABLE WITH THE ACTUATOR AND TRIP MEMBER, AND RESET LEVER MEANS ENGAGEABLE WITH THE COCKING LEVER MEANS ONLY WHEN THE COCKING LEVER MEANS IN A POSITION CORRESPONDING TO THE ACTUATED POSITION OF THE ACTUATOR, SAID RESET LEVER MEANS UPON ENGAGEMENT WITH THE COCKING LEVER MEANS CAUSING THE COCKING LEVER MEANS TO MOVE THE TRIP MEMBER TOWARD LATCHED POSITION WHILE HOLDING THE ACTUATOR IN ACTUATED POSITION. 